Melting furnace



Sept. 27, 1932. H. A. BRAssERT 1,880,012

MELTING FURNACE Filed July 27, 1931 2 sheets-sheet 1 H /y 4 aJ w Z l /JUMMNAMQM 1V. a f e ma W wf w y@ mi A M w @d j. l mw U fj w ,l m

Sept. 27, 1932. H. A. BRAssERT MELTING FURNACE Filed July 27, 1931 2 Sheets-Sheet 2 Patented Sept. 27, 1932 UNITED STATES PATENT OFFICE HERMAN A. BRASSERT, OF CHICAGO, ILLINOIS, .ASSIGNOR TO I-I. A. BRASSERT & COM- :PANY, or CHICAGO, ILLINois,

MELTING Application led July 27,

This invention relates to a new and improved melting furnace, and more particularly to a. melting furnace of the type comprising a vertical shaft superposed over an n enlarged hearth section.

I have shown certain furnaces of this type in my copending applications, Serial No. 541,492 filed June 15, 1931, and Serial No. 549,722, sied July 9, 1931.

In this type of furnace the materials are charged through the vertical stack section, are preheated in this Stack section, and are then melted in the hearth section. Combustion takes place in a space in the hearth section surrounding the lower portion of the descending column of materials. These materials are gradually melted away under the influence of the flames andhighly heated gases directly impinging against them, or

circulated around them. Molten materials are collected in the hearth and metal and slag are separated by gravity in the usual manner.

In a copending application, Serial No.

' 25 519,722 filed in the name of Fredrik lllille,

Iaul Zimmermann and myself, an annular' depression is shown around the circumference of the bath, which depression holds the molten metal and contains the bath during a refining stage of the process. In the center of the hearth is a circular shaped bottom on which the furnace charge drops prior to the conversion of the materials into the liquid state.

It is an object of the present invention to provide a new and improved furnace construction in which a ieat radiating back wall is located adjacent e bath to facilitate the refiningr operation..A

It is a furtherobject to provide a construction of this character in which the melting mass of materia-l is held above the level of molten metal and contamination of this metal prevented.

It is a further object to provide a furnace construction in which sections of the wall of the hearth portion may be removed and replaced as desired.

Other and further objects will appear as 50 the description proceeds.

A CORPORATION OF ILLINOIS FURNACE 1931. Serial No. 553,250.

I have shown a. preferred embodiment of my invention in the accompanying drawings, in whichy Figure 1 is a vertical section through the furnace;

Figure 2 is a horizontal section taken through the lower line of tuyres; and

Figure 3 is a plan view of the hearth portion partly in section, through the upper line of tuyres.

In the drawings, the stack portion 11 is shown as provided with a metal shell 12 and a refract ory lining 13, which is provided with water cooled bosh plates 14 which may be of usual construction. It will be understood that any usual type of charging bell may be located at the upper end of the stack portion, which will also be provided with ofitales for carrying off the products of combustion.

The stack portion is supported on the annular water cooled metal ring 15. rIhe hearth portion it is provided with a base 17 which may be formed of any usual refractory brick or other similar material, and which is enclosed in a water cooled metal jacket 18. The hearth is shown as covered with a lining 19 of refractory material which may be any of the types of material used in open hearth and similar furnaces. A tapping hole 20 is provided for removing the slag and a lower tapping hole 21 provided for use in removing the molten metal.

A plurality of doors 22 are provided at spaced points about the walls adjacent the slag line, these doors serving for cleanout and inspection purposes and also for the addition of any material which it may be desired to add to the bath during the refining process.

The central portion 23 of the hearth is raised and this, together with the layer of refractory material 19 on the central portion, causes this portion to extend to a level above that of the lower line of tuyres 24. These tuyeies are fed with air through pipes 25 leading from bustle pipe 26, and with fuel through pipes 27 fed from fuel header 28. As clearly shown in Figure 2, these tuyres 24 are located on lines approximately tan- 100 gential to the annular bath surrounding the raisedv central hearth portion 23 so that the flame from the tuyeres is directed down on the annular bath of metal and slag rather than toward the raised centra-l portion of the hearth. This causes a circular movement of the heated gases and enables the flame to be in contact with the bath over an extended space without burning out the refractory central portion. This refractory central portion 23 which serves as a back-wall for the annular bath may be provided with suitable cooling means, such as the pipes 29, to assist in maintaining it.

The upper curved wall portion 30 of the hearth section is shown as made up ofa lurality of segments 31, as best shown 1n 4igure 3. These segments are individually removable, being supported at their upper ends against the water cooled key ring 15 and at their lower ends by the water cooled flange 32 of the water cooled jacket 18 of the vertical Walls. These segments 3l are provided with a plurality of water cooled pipes 33, and their inner faces are formed by refraetory brick 34.

The upper series of tuyeres 35 extend through the curved portions, certain segments 36 being especially designed and provided with tuyre openings. The tuyeres 35 are fed with air through pipes 37 from the bustle pipe 26, and with fuel through pipe 38 from header 28. As clearly shown in Figure 3, these tuyrcs 35 are preferably placed slightly off of an exact radial line so as to insure a circulatory movement of the gases and yet they are not placed tangentially as the lower tuyeres, as it is desired to direct the flame from the upper tuyeres against the central column of descending material.

A third set of tuyeres 39 discharge through small openings 40 into the upper portion of the domed section of the hearth. These tuyeres 39 are supplied through pipe 41 from the bustle pipe 42. These tuyeres ar-e normally supplied with burned gases or other inert gases which will not burn, and which gases form a protective layer adjacent the inner surface of the domed hearth wall to protect this surface against erosion by the heated products of combustion from the two lower sets of tuyeres. A further possible use of the small tuyeres 39 consists in the fact that should the stack portion become clogged, these tuyeres can be used to carry off a portion of the products of combustion, thus relieving the fiow through the stack. y

This raising of the center portion of the hearth as shown herein enables the system of refining of the moltenmetal to be carried on independently of, and unaffected by, the entrance of melting materials into the refining phase of the process. The descending column of materials is supported on the pedestal and this will prevent them being dissolved in the molten bath during the refinir'ig period; It will be evident that when operating with the two rows of tuyeres shown, by shutting off the blast and fuel in the upper row,y melting will be practically stopped, While the lower tuyres are used for refining. During this period the unmelted materials will be supported on the center pedestal and will not be immersed in the bath, cooling it and polluting it with unrefined melting materials.

A single row of tuyeres may be employed, the upper row of tuyeres 35 being omitted, and in this case the pedestal is equally useful. The single row of tuyeres 24 remaining are located close to the bath and will be first used for melting with a flame of suitable character, and then for refining with a flame especially adapted for this purpose.

With the material resting on the raised pedestal it is evident that durin the refining period melting will be stoppe or at least greatly retarded. The raised pedestal can be of any suitable refractory material and may be properly cooled to prevent its disintegration. Its height depends upon the position of the tuyeres and should preferably be such that the upper melting tuyeres converge in a plane above it.

The construction of the upper domed wall of the hearth in a plurality of removable sections provides a construction whereby repairs can be made to the hearth in the shortest possible space of time. Such repairs can be made between melting and refining periods or after such periods have been completed without materially cooling the hearth and the shaft of the furnace. As many narrow segments as desired can be unbolted and removed and new segments inserted and bolted into place without material delay in operation.

While I have shown a preferred form of construction, it is to be understood that this is by way of example only, as I contemplate such changes and modifications as come Within the spirit and scope of the appended claims.

I claim:

1. In a metallurgical furnace, a hearth chamber, a raised portion located centrally of the hearth chamber, an annular metal holding recess surrounding the raised portion in the chamber, and tuyeres extending into the hearth.

2. In a metallurgical furnace, a hearth chamber, a raised portion located centrally of the hearth chamber, an annular metal holding recess surroundin the raised portion in the. chamber, and tuyeres extending into the hearth, the raised portion extending above the plane of the tuyeres.

3. In a metallurgical furnace, a hearth, a raised portion located centrally of the hearth, tuyeres extending into the hearth and located below the plane of the raised portion, and a second set of tuyres located above the plane of the raised portion.

4. In a metallurgical furnace, a hearth, a

-. raised portion located centrally of the hearth and forming an annular recess for retaining a bath of molten metal adjacent the Walls, and tuyres directed through the walls and tangentially upon the annular recess.

5. In a metallurgical furnace, a hearth, a raised portion located centrally of the hearth and forming an annular recess for retaining a bath of molten metal adjacent the walls, and tuyres directed through the walls and tangentially upon the annular recess, the central raised portion extending above the plane of the tuyres and serving as a back wall for the annular recess.

6. In a metallurgical furnace, a hearth chamber, a shaft portion located centrally above the hearth chamber, a raised central portion of the hearth floor located beneath the shaft portion, an annular metal holding recess surrounding the central portion adjacent the hearth walls, and tuyres below the level of the central portion and directed upon the metal holding recess.

7. In a metallurgical furnace, a hearth chamber, a shaft portion located centrally above the hearth chamber, araised central portion of the hearth floor located beneath the shaft portion, an annular metal holding recess surrounding the central portion adjacent the hearth walls, and tuyres below the level of the central portion and directed upon the metal holding recess, said tuyres extending substantially tangentially of the hearth.

8. In a metallurgical furnace, a hearth, a shaft portion located centrally above the hearth, a raised central portion of the hearth located beneath the shaft portion, an annular metal receivin recess surrounding the central portion adjacent the hearth walls, tuyres below the level ofthe central portion and directed upon the metal receiving recess, and a second set of tuyres located above the level of the central portion and directed inwardly to cause a flame to engage a mass of material supported upon the central portion.

9. In a metallurgical furnace, a hearth, a shaft portion located centrally above the hearth, a raised central ortion of the hearth located beneath the sha t portion, an annular metal receivin recess surroundin the central portion adjacent the hearth wa ls,tuyres below the level of the central ortion and directed upon the metal receivlng recess, and a second set of .tuyres located above the level of the central portion and directed inwardly to cause a flame to engage a mass of material supported upon the central portion, said upper tuyres bein directed non-radiall of the hearth. g y

10. In a metallurgical furnace, a hearth having a dome-shaped roof, a plurality of separate, removable metallic Water cooled sections lined with refraetory material forming said roof.

11. In a metallurgical furnace, a hearth having al dome-shaped roof, a plurality of separate, removable sections forming said roof, and a water cooled metallic ring serving as a key member to support the upper ends of said sections.

12. In a. metallurgical furnace, a hearth portion, a reduced shaft portion, tuyres eX- tending into the hearth for introducing fuel and air, and other tuyre openings in the upper portion of the hearth adapted selectively to introduce inert gases or to draw 0E .a portion of the products of combustion.

Signed at Chicago, Illinois, this 24th day of July, 1931.

HERMAN A. BRASSERT.

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